Earthquake Introduction
- 2. Introduction • Earthquake is a natural disaster, occurs due to sudden shaking of ground caused by passage of seismic waves through earth rocks, which results movements tectonic plates. • It is associated with faulting or breaking of rocks. • Seismic waves produced when some form of energy stored in earth crust is suddenly released. • Most earthquake occur along the edge of the oceanic and continental plate. Definitions: • Earthquake-vibration of earth produced by rapid release of energy. • Seismic waves-Energy moving outward from the focus of an earthquake
- 4. Technical terms • Lithosphere • Focus • Epicenter • Seismic waves • Seismometer • Seismograph • Seismogram • Magnitude : Richter Scale • Intensity : Mercalli’s Scale • Fault : Strike-slip
- 5. • Focus-The point within earth surface where faulting begins is the focus or hypocenter. • Epicenter-The point directly above the focus on the surface is the epicenter. • Fault -A planar or curved fracture in the rocks of the earth crust, where compressional or tensional forces cause relative displacement of the rocks on opposite sides of the fracture.
- 6. Seismic Waves • Seismic waves are energy waves that move through the earth. • It is useful to study the structure of the earth by monitoring how the wave pass to the interior of the earth. Types Body Waves Travel through the interior earth and move faster than surface waves. P-Wave-primary or compression wave S-Wave-transverse or shear wave Surface Waves Long Wave Rayleigh Wave
- 8. Measuring Instrument • Seismometer-Detects seismic waves • Seismograph-Records intensity, Height and amplitude of seismic waves. • Seismogram-Graphical output of seismograph. Measurements Magnitude-measured value of the earthquake size. • one per earthquake • Related to energy released • Richter or moment scale Intensity-Measure of shaking created by the earthquake, values vary with locations. • Many for each earthquake • Measures of effects • Mercalli Scale
- 9. Classification of Earthquake Measurements
- 10. Causes of Earthquake • Volcanic activities • Folding and faulting • Plate tectonics movements • Human interface with nature( Mining, Drilling, Explosives etc..) Largest Earthquake(world): Instrumentally documented in southern Chile on may22,1960 at the magnitude of 9.5.Referred as “The Great Chilean earthquake”. Important places for earthquake around world: • 90% of world earthquake occurs in “Ring of fire”. • Next most seismic region-Mediterranean region(5-6%) • Estimation: Each year 5,00,000 are detectable.100 of them cause damage.
- 11. IN INDIA Gujarat : Bhuj Earthquake(Epicenter) 7.7 Richter scale, Jan 2001,(2 minutes) Time:8.40 AM Maharashtra : Kilari in Latur district(Epicenter) 6.2 ,Sep 1993. Time:3.56AM,Depth:10km Bihar : Near Eastern Nepal(Epicenter) 8.0 ,Jan 15,1934. Time:2.28PM,Depth:15Km Uttarkashi : Uttarkashi and Bash Wari region(Epicenter) 6.1,Oct 20,1991 Time:2.53AM,Depth:11.6Km
- 12. Death Ground motion Poor Construction of building Landslide Rupture Fire Effects
- 13. • Earthquake zones of India
- 14. REFERENCE • https://earthquake.usgs.gov/learn/facts.php • https://www.quora.com/What-causes-earthquakes • https://www.britannica.com/science/earthquake-geology • https://www.conserve-energy-future.com/howearthquakesoccur.php • http://paleoseismicity.org/things-that-cause-earthquakes/ • https://www.srmbsteel.com/content/4-disastrous-earthquakes-shook-india • http://asc-india.org/seismi/seis-tamil-nadu.htm • http://asc-india.org/seismi/seis-tamil-nadu.htm • https://www.iris.edu/hq/files/programs/education_and_outreach/aotm/8/Seismogr aph_Background.pdf